Existing sensing and therapeutic devices can have limited applicability due to a lack of sophistication related to the sensing, imaging, and therapeutic functions. The precision and speed of sensing, imaging and therapeutic functions is beneficial for treating certain cardiac diseases, such as atrial fibrillation.
According to some research, atrial fibrillation (AF) affects 5 million patients in the developed world and is the leading cause of stroke in cardiac patients. With up to 400,000 new cases diagnosed yearly, the adverse outcomes of various types of AF range from congestive heart failures to sudden death. Catheter ablation techniques have become increasingly prevalent as interventional strategies for treating various forms of cardiac arrhythmia, including AF, ventricular fibrillation (VF), and ventricular tachycardia (VT). Some catheter ablation techniques generate linear lesions in a “point-by-point” fashion with radio frequency (RF) electrodes; however, such techniques have not had an effective success rate in patients with persistent AF, at least in part because the ablation targets are not well defined because the techniques are generally lengthy procedure requiring highly skilled operators to minimize risk of stroke and other clinical complications. Current ablation targets in persistent AF include areas exhibiting “complex fractionated atrial electrograms” (CFAEs). These are electrical recordings with a highly disorganized appearance. It is believed that CFAEs represent rapid electrical activity from a nearby driving force (rotor).
Studies on isolated hearts using high resolution optical mapping have revealed the presence of rotors (re-entrant circuits) as an underlying mechanism for AF. It is believed that high-frequency impulses emanating from the rotors are subject to spatially distributed intermittent blockade imposed by the presence of functional and anatomical obstacles in their path, resulting in the seemingly disorganized activity that characterizes AF. Thus far, the demonstration of rotors in the clinical setting has been limited by the lack of high resolution voltage mapping. As a result, treatment strategies, such as catheter ablation, remain marginally effective in persistent AF cases because of the inability to define clear targets.